1 /* Common subexpression elimination for GNU compiler.
2 Copyright (C) 1987-2023 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
10
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
19
20 #ifndef GCC_CSELIB_H
21 #define GCC_CSELIB_H
22
23 /* Describe a value. */
24 struct cselib_val
25 {
26 /* The hash value. */
27 unsigned int hash;
28
29 /* A unique id assigned to values. */
30 int uid;
31
32 /* A VALUE rtx that points back to this structure. */
33 rtx val_rtx;
34
35 /* All rtl expressions that hold this value at the current time during a
36 scan. */
37 struct elt_loc_list *locs;
38
39 /* If this value is used as an address, points to a list of values that
40 use it as an address in a MEM. */
41 struct elt_list *addr_list;
42
43 struct cselib_val *next_containing_mem;
44 };
45
46 /* A list of rtl expressions that hold the same value. */
47 struct elt_loc_list {
48 /* Next element in the list. */
49 struct elt_loc_list *next;
50 /* An rtl expression that holds the value. */
51 rtx loc;
52 /* The insn that made the equivalence. */
53 rtx_insn *setting_insn;
54 };
55
56 /* Describe a single set that is part of an insn. */
57 struct cselib_set
58 {
59 rtx src;
60 rtx dest;
61 cselib_val *src_elt;
62 cselib_val *dest_addr_elt;
63 };
64
65 enum cselib_record_what
66 {
67 CSELIB_RECORD_MEMORY = 1,
68 CSELIB_PRESERVE_CONSTANTS = 2
69 };
70
71 extern void (*cselib_discard_hook) (cselib_val *);
72 extern void (*cselib_record_sets_hook) (rtx_insn *insn, struct cselib_set *sets,
73 int n_sets);
74
75 extern cselib_val *cselib_lookup (rtx, machine_mode,
76 int, machine_mode);
77 extern cselib_val *cselib_lookup_from_insn (rtx, machine_mode,
78 int, machine_mode, rtx_insn *);
79 extern void cselib_init (int);
80 extern void cselib_clear_table (void);
81 extern void cselib_finish (void);
82 extern void cselib_process_insn (rtx_insn *);
83 extern bool fp_setter_insn (rtx_insn *);
84 extern machine_mode cselib_reg_set_mode (const_rtx);
85 extern int rtx_equal_for_cselib_1 (rtx, rtx, machine_mode, int);
86 extern bool cselib_redundant_set_p (rtx);
87 extern int references_value_p (const_rtx, int);
88 extern rtx cselib_expand_value_rtx (rtx, bitmap, int);
89 typedef rtx (*cselib_expand_callback)(rtx, bitmap, int, void *);
90 extern rtx cselib_expand_value_rtx_cb (rtx, bitmap, int,
91 cselib_expand_callback, void *);
92 extern bool cselib_dummy_expand_value_rtx_cb (rtx, bitmap, int,
93 cselib_expand_callback, void *);
94 extern rtx cselib_subst_to_values (rtx, machine_mode);
95 extern rtx cselib_subst_to_values_from_insn (rtx, machine_mode, rtx_insn *);
96 extern void cselib_invalidate_rtx (rtx);
97
98 extern void cselib_reset_table (unsigned int);
99 extern unsigned int cselib_get_next_uid (void);
100 extern void cselib_preserve_value (cselib_val *);
101 extern bool cselib_preserved_value_p (cselib_val *);
102 extern void cselib_preserve_only_values (void);
103 extern void cselib_preserve_cfa_base_value (cselib_val *, unsigned int);
104 extern void cselib_add_permanent_equiv (cselib_val *, rtx, rtx_insn *);
105 extern bool cselib_have_permanent_equivalences (void);
106 extern void cselib_set_value_sp_based (cselib_val *);
107 extern bool cselib_sp_based_value_p (cselib_val *);
108 extern void cselib_record_sp_cfa_base_equiv (HOST_WIDE_INT, rtx_insn *);
109 extern bool cselib_sp_derived_value_p (cselib_val *);
110
111 extern void dump_cselib_table (FILE *);
112
113 /* Return the canonical value for VAL, following the equivalence chain
114 towards the earliest (== lowest uid) equivalent value. */
115
116 inline cselib_val *
117 canonical_cselib_val (cselib_val *val)
118 {
119 cselib_val *canon;
120
121 if (!val->locs || val->locs->next
122 || !val->locs->loc || GET_CODE (val->locs->loc) != VALUE
123 || val->uid < CSELIB_VAL_PTR (val->locs->loc)->uid)
124 return val;
125
126 canon = CSELIB_VAL_PTR (val->locs->loc);
127 gcc_checking_assert (canonical_cselib_val (canon) == canon);
128 return canon;
129 }
130
131 /* Return nonzero if we can prove that X and Y contain the same value, taking
132 our gathered information into account. */
133
134 inline int
135 rtx_equal_for_cselib_p (rtx x, rtx y)
136 {
137 if (x == y)
138 return 1;
139
140 return rtx_equal_for_cselib_1 (x, y, VOIDmode, 0);
141 }
142
143 #endif /* GCC_CSELIB_H */